Medical devices and methods incorporating frustrated total internal reflection for energy-efficient sealing and cutting of tissue using light energy

ABSTRACT

A medical instrument includes two jaw members, at least one of which creates conditions of frustrated total internal reflection at a tissue-contacting surface when tissue is grasped between the two jaw members. The first jaw member may include an optical element having a tissue-contacting surface. The medical instrument also includes a light source that provides a light beam for sealing tissue. The light source is positioned so that the light beam is totally internally reflected from an interface between the tissue-contacting surface and air when tissue is not grasped by the jaw members. When tissue is grasped by the jaw members, at least a portion of the light beam is transmitted through that portion of the tissue-contacting surface that is in contact with the tissue. The light source may be movably coupled to a jaw member to scan the light beam and/or to change the incident angle based on optical properties of the tissue.

CROSS REFERENCE TO RELATED APPLICATION

The present application claims the benefit of and priority to U.S.Provisional Application Ser. No. 61/697,671, filed on Sep. 6, 2012, theentire contents of which are incorporated herein by reference.

BACKGROUND

1. Technical Field

The present disclosure relates to medical devices having components totreat tissue with light energy. More particularly, the presentdisclosure relates to open or endoscopic surgical forceps thatincorporate optics to create conditions of frustrated total internalreflection to facilitate energy-efficient sealing and cutting of tissueusing light energy.

2. Description of Related Art

In many surgical procedures, body vessels, e.g., blood vessels, ducts,adhesions, fallopian tubes, or the like are sealed to defunctionalize orclose the vessels. Traditionally, staples, clips or sutures have beenused to close a body vessel. However, these traditional procedures oftenleave foreign body material inside a patient. In an effort to reduceforeign body material left within the patient and to more effectivelyseal the body vessel, energy techniques that seal by heating tissue havebeen employed.

Endoscopic or open forceps are particularly useful for sealing sinceforceps utilize mechanical action to constrict, grasp, dissect and/orclamp tissue. Current vessel sealing procedures utilize radio frequencytreatment to heat and desiccate tissue causing closure and sealing ofvessels or tissue.

SUMMARY

As used herein, the term “distal” refers to that portion that is furtherfrom an operator while the term “proximal” refers to that portion thatis closer to an operator. As used herein, the term “treat” refers toperforming a surgical treatment to tissue including, but not limited toheating, sealing, cutting, sensing, and/or monitoring.

As used herein, the term “light source” broadly refers to all types ofdevices or elements that generate or transmit light for medical use(e.g., tissue treatment). These devices include lasers, light emittingdiodes (LEDs), lamps, and other devices that generate light having awavelength that is within the light spectrum (e.g., from infrared lightto ultraviolet light). Also, the light sources described herein may beused interchangeably. For example, an LED light source may be usedinterchangeably with a laser light source.

Light sources may produce laser light having a wavelength from about 200nm to about 15,000 nm and include but are not limited to ruby lasers,tunable titanium-sapphire lasers, copper vapor lasers, carbon dioxidelasers, alexandrite lasers, argon lasers such as argon fluoride (ArF)excimer lasers, argon-dye lasers, potassium titanyl phosphate (KTP)lasers, krypton lasers such as krypton fluoride (KrF) excimer lasers,neodymium:yttrium-aluminum-garnet (Nd:YAG) lasers, holmium:yttrium-aluminum-garnet (Ho:YAG) lasers, erbium:yttrium-aluminum-garnet(Er:YAG) lasers, diode lasers, fiber lasers, xenon chloride (XeCl)excimer lasers, tubanle thalium lasers, and any combinations of theselasers. Additional types of light sources include fiber optic lightsources and deuterium light sources.

In some embodiments, a light source may generate light of multiplewavelengths. For example, Nd:YAG and KTP laser light may be generated bya single laser source. Nd:YAG laser light, which has a large opticaldepth or thickness, may be used for sealing and KTP laser light, whichhas a small optical depth or thickness, may be used for cutting or forsealing small vessels or thin tissue.

As described in more detail below with reference to the accompanyingfigures, the present disclosure relates to open or endoscopic surgicalforceps that incorporate optics to create conditions of frustrated totalinternal reflection to facilitate energy-efficient sealing and cuttingof tissue using light energy. In some embodiments, one or both jawmember of the surgical forceps is optically designed so that light of atherapeutic wavelength, e.g., infrared laser light having a wavelengthbetween 800 nm and 1550 nm, is totally internally reflected from theboundary between a tissue-contacting surface of one or both jaw membersand air, when tissue is not grasped by the surgical forceps. Thiscreates an evanescent wave on the tissue-contacting surface of one orboth jaw members.

When tissue is grasped by the surgical forceps, the tissue-contactingsurface of one or both jaw members comes into contact with the tissueand the evanescent wave allows light energy to be transmitted to thetissue only through those portions of the tissue-contacting surface thatare in contact with the tissue. The light energy is absorbed by thetissue resulting in heat that is used to fuse tissue (e.g., sealing)and/or separate tissue (e.g., cutting). As a result, light energy isefficiently delivered to the tissue because there is a decreased amountof wasted or lost light energy.

In some embodiments, the surgical devices sense and/or monitor thetissue during a surgical procedure to determine when a seal cycle iscomplete, to determine the efficacy of a tissue seal and/or to measurejaw pressure. In some embodiments, tissue separation may be accomplishedwith the same light energy device used for tissue sealing, therebyeliminating the need for a separate mechanical blade that istraditionally used for tissue separation in jaw members.

In aspects, the present disclosure features a medical instrument. Themedical instrument includes a first jaw member having atissue-contacting surface and a second jaw member movably coupled to thefirst jaw member. The first jaw member and the second jaw membercooperate to grasp tissue between the first jaw member and the secondjaw member. The medical instrument further includes a light source thatprovides a light beam for sealing tissue. The light source is opticallycoupled to the first jaw member so that the light beam is internallyreflected from the interface between the tissue-contacting surface ofthe first jaw member and air when tissue is not grasped between thefirst jaw member and the second jaw member. The light source is alsooptically coupled to the tissue-contacting surface of the first jawmember so that at least a portion of the light beam is transmittedthrough that portion of the tissue-contacting surface of the first jawmember that is in contact with the tissue when the tissue is graspedbetween the first jaw member and the second jaw member.

The light source of the medical instrument may include an optical fiber,a light-emitting diode, a laser, a diode laser, a fiber laser, or anycombination of these light sources. The light source may be configuredto rotate and/or translate with respect to the first jaw member. Thelight source may also be configured to scan the tissue with the lightbeam.

The second jaw member of the medical instrument may include alight-absorbent material that absorbs light that is transmitted throughthe tissue. Alternatively, the second jaw member may include alight-reflective material that reflects light that is transmittedthrough the tissue. The light-absorbent material or the light-reflectivematerial may be coated onto the surface of the second jaw member.

The light source may be movable and may be configured to move to aposition based on at least one optical property of the tissue while thetissue is in contact with at least a portion of the tissue-contactingsurface of the first jaw member. The at least one optical property ofthe tissue may include index of refraction, absorption coefficient,scattering coefficient, anisotropy coefficient, or any combination ofthese optical properties. The light source may be rotatable toselectively provide a light beam having a variable angle of incidencewith respect to an axis normal to the tissue-contacting surface of thefirst jaw member.

The medical instrument may further include an optical element disposedin the first jaw member and having a side that forms at least a portionof the tissue-contacting surface of the first jaw member. The opticalelement may be a light guide that extends along at least a portion of alongitudinal axis of the first jaw member. A light-absorbent element ora light-reflective element may be coupled to at least a portion of adistal end of the light guide. The optical element may be a crystalconfigured to circulate the light provided by the light source whentissue is not grasped between the first jaw member and the second jawmember.

The optical element may include a plurality of crystals and the lightsource may include a plurality of light sources coupled to the pluralityof crystals, respectively. Each of the plurality of light sources may beconfigured to provide a light beam having a different wavelength.

The optical element may be formed of a material including sapphire,ruby, YAG, alexandrite, flint, BK7 glass, fused silica, or anycombination of these materials.

The second jaw member of the medical instrument may include a secondoptical element having a side that forms at least a portion of a secondtissue-contacting surface. The medical instrument may further include asecond light source that provides a second light beam for sealingtissue. The second light source is optically coupled to the secondoptical element so that the second light beam is totally internallyreflected from the interface between the second tissue-contactingsurface of the second optical element and air when tissue is not graspedbetween the first jaw member and the second jaw member. The second lightsource may also be optically coupled to the second optical element sothat at least a portion of the second light beam is transmitted throughthat portion of the second tissue-contacting surface of the secondoptical element that is in contact with the tissue when the tissue isgrasped between the first jaw member and the second jaw member.

The first jaw member of the medical instrument may be hollow and theoptical element may be disposed within the first jaw member.Alternatively, the optical element may form at least a portion of thefirst jaw member.

In yet other aspects, the present disclosure features an optical-basedtissue-sealing system. The optical-based tissue-sealing system includesa housing and an end effector assembly operably connected to thehousing. The end effector assembly includes a first jaw member having atissue-contacting surface. The end effector assembly also includes asecond jaw member movably coupled to the first jaw member. The first jawmember and the second jaw member cooperate to grasp tissue between thefirst jaw member and the second jaw member.

The optical-based tissue-sealing system also includes a light sourcethat provides a light beam for sealing tissue. The light source isoptically coupled to the tissue-contacting surface so that the lightbeam is totally internally reflected from an interface between thetissue-contacting surface of the first jaw member and air when tissue isnot grasped between the first jaw member and the second jaw member. Thelight source is also optically coupled to the first jaw member so thatat least a portion of the light beam is transmitted through thetissue-contacting surface of the first jaw member to the tissue whentissue is grasped between the first jaw member and the second jawmember. The optical-based tissue-sealing system further includes acontroller coupled to the light source. The controller controls at leastone parameter of the light beam. The one or more parameters of the lightbeam may include intensity, wavelength, polarization, angle of incidencewith respect to an axis normal to the tissue-contacting surface of thefirst jaw member, or any combination of these parameters.

The optical-based tissue-sealing system may further include a sensorthat senses at least one optical property of the tissue and thecontroller may further control at least one parameter of the light beambased upon the at least one optical property of the tissue.

In yet other aspects, the present disclosure features a method oftreating tissue with an optical energy-based medical instrument. Themethod includes directing a light beam into at least one optical elementof a first jaw member of an optical energy-based instrument with a lightbeam, reflecting the light beam within the optical element from aninterface between a surface of the optical element and a media having alow index of refraction, grasping tissue between the first jaw memberand a second jaw member of an optical energy-based medical instrument,and transmitting at least a portion of the light beam through atissue-contacting surface of the optical element to the tissue when thetissue is grasped between the first jaw member and the second jawmember.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the medical systems, devices, instruments, andmethods are described herein with reference to the drawings wherein:

FIG. 1A is a perspective view of an optical-based surgical systemincluding a surgical instrument having an end effector assembly thatincorporates optical components for creating conditions of frustratedtotal internal reflection within one or more jaw members of the endeffector assembly according to embodiments of the present disclosure;

FIG. 1B is a perspective view of a cordless, optical-based surgicalinstrument having an end effector assembly that incorporates opticalcomponents for creating conditions of frustrated total internalreflection within one or more jaw members of the end effector assemblyaccording to embodiments of the present disclosure;

FIGS. 2A and 2B are schematic side, cross-sectional views of an endeffector assembly according to embodiments of the present disclosure;

FIGS. 3A and 3B are schematic side, cross-sectional views of jaw membersaccording to embodiments of the present disclosure;

FIGS. 4A and 4B are schematic side, cross-sectional views of jaw membersincorporating fiber optic components in both jaw members according toembodiments of the present disclosure;

FIGS. 5A-5C are schematic side, cross-sectional views of jaw members,one of which includes an optical element and a movable light source,according to embodiments of the present disclosure;

FIGS. 6A-6B are schematic side, cross-sectional views of jaw membersincluding an optical element that forms a portion of a jaw memberaccording to embodiments of the present disclosure;

FIG. 7 is a schematic side, cross-sectional view of jaw members, one ofwhich incorporates a light guide, according to embodiments of thepresent disclosure;

FIG. 8 is a schematic side, cross-sectional view of jaw members, one ofwhich includes a plurality of optical elements according to embodimentsof the present disclosure; and

FIGS. 9 and 10 are flow diagrams of methods of performing tissue sealingaccording to embodiments of the present disclosure.

DETAILED DESCRIPTION

Embodiments of the presently-disclosed surgical instrument are describedin detail with reference to the drawings wherein like reference numeralsidentify similar or identical elements.

FIG. 1A shows an endoscopic surgery forceps 10 that may be used with anyof the embodiments of end effector assemblies described below. In FIG.1A, forceps 10 is coupled to a light energy source (e.g., a generator40) for generating light energy adapted to seal tissue. Light energysource (e.g., generator 40) is configured to output light energy havinga wavelength from about 200 nm to about 11,000 nm. Forceps 10 is coupledto the generator 40 via a cable 34 that includes one or more opticalfibers to transmit light energy and one or more electrical conductors totransmit control signals between the forceps 10 and the generator 40.The generator 40 may produce light energy having one or morewavelengths. In some embodiments, Nd:Yag and KTP laser light may beproduced by the same laser source. Various embodiments of the forceps 10using the light energy are described below.

Forceps 10 is configured to support an end effector assembly (e.g., endeffector assembly 100) at a distal end thereof. Forceps 10 includesvarious conventional features (e.g., a housing 20, a handle assembly 22,a trigger assembly 25, and a rotating assembly 28) that enable forceps10 and end effector assembly 100 to mutually cooperate to grasp, seal,divide and/or sense tissue. Forceps 10 generally includes housing 20 andhandle assembly 22 that includes movable handle 24 and a handle 26 thatis integral with housing 20. The handle 24 is movable relative to thehandle 26 to actuate end effector assembly 100 via a drive assembly (notshown) to grasp tissue.

In some embodiments, trigger assembly 25 may be configured to actuate aknife blade (not shown) or another component. Forceps 10 also includesshaft 12 having a distal portion 16 that mechanically engages endeffector assembly 100 and a proximal portion 14 that mechanicallyengages housing 20 proximate rotating assembly 28 disposed on housing20. Rotating assembly 28 is mechanically associated with shaft 12 suchthat rotational movement of rotating assembly 28 imparts similarrotational movement to shaft 12 that, in turn, rotates end effectorassembly 100.

End effector assembly 100 includes two jaw members 110 and 120, eachhaving proximal ends 110 a, 120 a and distal ends 110 b, 120 b,respectively (see FIG. 1A). One or both jaw members 110 and 120 arepivotable about a pin 19 and one or both are movable from a firstposition wherein jaw members 110 and 120 are spaced relative to another,to a second position wherein jaw members 110 and 120 are closed andcooperate to grasp tissue between the jaw members 110 and 120.

Each jaw member 110 and 120 includes a tissue contacting surface 211 and212, respectively, disposed on an inner-facing surface thereof (see FIG.2A). Tissue-contacting surfaces 211, 212 cooperate to grasp and sealtissue held between the tissue-contacting surfaces. Tissue-contactingsurfaces 211, 212 are connected to generator 40 that can transmit lightenergy through the tissue held between the tissue-contacting surfaces211, 212.

First and second switch assemblies 30 and 32 are configured toselectively provide light energy to end effector assembly 100. Moreparticularly, the first switch assembly 30 may be configured to performa first type of surgical procedure (e.g., seal, cut, and/or sense) and asecond switch assembly 32 may be configured to perform a second type ofsurgical procedure (e.g., seal, cut, and/or sense). It should be notedthat the presently-disclosed embodiments may include any number ofsuitable switch assemblies and are not limited to only switch assemblies30 and 32. It should further be noted that the presently-disclosedembodiments may be configured to perform any suitable surgical procedureand are not limited to only sealing, cutting and sensing.

The housing 20 further includes one or more light-transmissive elements,such as one or more optical fibers disposed within a cable 34 thatconnects the forceps 10 to the generator 40. The cable 34 may include aplurality of optical fibers (not shown) that are configured to transmitlight energy through various paths and ultimately to end effectorassembly 100 and one or more optical elements that are configured tocreate conditions of total internal reflection at one or both of thetissue contacting surfaces 211 and 212.

First and second switch assemblies 30 and 32 may also cooperate with acontroller 42, which may be implemented by a logic circuit, a computer,a processor, and/or a field programmable gate array. The controller 42may automatically trigger one of the switches to change between a firstmode (e.g., sealing mode) and a second mode (e.g., cutting mode) uponthe detection of one or more parameters, properties, or thresholds. Insome embodiments, the controller 42 is also configured to receivevarious sensor feedback and to control the generator 40 based on thesensor feedback. The embodiments of the present disclosure allow the jawmembers 110 and 120 to seal and/or cut tissue using light energy.

In some embodiments, the controller 42 may include a feedback loop thatindicates when a tissue seal is complete based upon one or more of thefollowing parameters or properties: tissue temperature, change inimpedance of the tissue over time, change in optical characteristics oftissue (opaqueness, clarity, etc.), rate of change of these properties,and combinations thereof. An audible or visual feedback monitor may beemployed to convey information to the surgeon regarding the overall sealquality or the completion of an effective tissue seal.

Referring now to FIG. 1B, forceps 10 is shown having a portableconfiguration and includes an internal energy source 50 for generatinglight energy that is operably coupled to a battery compartment 52 viaone or more wires 50 a. In some embodiments, one or morebattery-operated laser diodes or fiber lasers may also be used toprovide a portable light energy source. Internal energy source 50 may beconfigured to provide light energy to the end effector assembly 100 andoptical elements via one or more laser fibers 50 b or any other suitabletransmission medium. Battery compartment 52 may be configured to receiveone or more batteries 54 for providing suitable energy to internalenergy source 50. In embodiments, the controller 42 may also be disposedwithin the forceps 10 (e.g., housing).

Battery compartment 52 may be defined within any suitable portion ofhousing 20 of forceps 10, such as the fixed handle 26, as shown in FIG.1B. Suitable batteries may include, but are not limited to anickel-cadmium, lithium-ion, rechargeable, or any other suitable type.The location of internal energy source 50 provides an operator increasedmaneuverability and convenience when performing a surgical treatmentwith forceps 10.

FIG. 2A illustrates an end effector assembly 200 according to thepresent disclosure, which is configured for use with instrument 10 ofFIG. 1A, instrument 11 of FIG. 1B, or any other suitable surgicalinstrument. The end effector assembly 200 includes jaw members 110 and120 having proximal ends 110 a, 120 a and distal ends 110 b, 120 b. Thefirst jaw member 110 (e.g., a top jaw member) has a firsttissue-contacting surface 211 and the second jaw member 120 (e.g., abottom jaw member) has a second tissue-contacting surface 212. The firstjaw member 110 and the second jaw member 120 are movable with respect toeach other so that tissue can be grasped between the firsttissue-contacting surface 211 and the second tissue-contacting surface212.

According to the various embodiments of the present disclosure, incidentlight beam 214 is directed at the tissue-contacting surface 211 of thefirst jaw member 110 from within the first jaw member 110. The incidentlight beam 214 is directed at a predetermined angle θ_(i) with respectto the axis 202 perpendicular to the tissue-contacting surface 211 ofthe first jaw member 110 so that the incident light beam 214 are totallyreflected as reflected light beams 217 at the interface between thetissue-contacting surface 211 and the air 205, e.g., when thetissue-contacting surface 211 is not in contact with tissue. Thetissue-contacting surface 211 may be made of a material, e.g., coatedwith a material, that enables total reflection of the incident lightbeam 214 when the tissue-contacting surface 211 is not in contact withtissue.

Refraction and reflection at a planar boundary or interface between twomedia of different refractive indices is described by Snell's law andFresnel's equations, which are related to Maxwell's wave equations forelectromagnetic radiation at a boundary or interface. As shown in FIG.2A, for refraction from the tissue-contacting surface 211 of the firstjaw member 110 with refractive index n₂, to air 205 with lowerrefractive index n₁, Snell's law provides the following relationship:

n ₂ sin θ_(i) =n ₁ sin θ_(r)

where θ_(i) is the angle of incidence and θ_(r) is the angle ofrefraction.

Total internal reflection occurs at the interface or boundary 230defined by the first tissue-contacting surface 211 and the air 205 whenthe angle of incidence θ_(i) (204) is greater than or equal to acritical angle θ_(c) (203), which is defined by the following equation:

θ_(c)=arcsin(n ₂ /n ₁).

This reflection is “total” because a certain amount of energy is presentin the air 205 in a thin layer adjacent to the boundary 230. As shown inFIG. 2A, this energy is in the form of evanescent waves 218. The wavesin this layer are called evanescent waves because they decay rapidly tozero.

When tissue 213 is not in contact with the tissue-contacting surface 211of the first jaw member 110, the reflected light beams 214 are containedwithin the first jaw member 110 so that they are not transmitted outsideof the first jaw member 110. In some embodiments, the inner or outersurfaces of the first jaw member 110 are coated with a light-reflectiveor a light-absorbent material to prevent the totally reflected lightbeam 216 from being transmitted outside of the first jaw member 110.

As shown in FIG. 2B, when tissue 213 is grasped between the firsttissue-contacting surface 211 and the second tissue-contacting surface212, the tissue 213 comes into contact with the first tissue-contactingsurface 211, thus forming a new interface 240 between the firsttissue-contacting surface 211 and the tissue 213. Because the index ofrefraction of tissue 213 (e.g., 1.5) is much greater than the index ofrefraction of air (e.g., 1.0), the total internal reflection is“frustrated” and the evanescent wave 218 transfers light energy from thelight beam 214 to the tissue 213.

In other words, a new critical angle 203 is defined by the followingequation:

θ_(c)=arcsin(n ₂ /n ₃),

where n₂ is the index of refraction of the tissue-contacting surface 211of the first jaw member 110 and n₃ is the index of refraction of thetissue 213. This new critical angle 203 is greater than the angle ofincidence of the light beam 214. As a result, a transmitted portion 215of the light beam 214 is transmitted to the tissue 213 and the remainingreflected portion 217 of the light beam 214 is reflected from the newinterface between the first tissue-contacting surface 211 and the tissue213.

Thus, as illustrated in FIGS. 2A and 2B, the incident light beam 214passes through that portion of the tissue-contacting surface 211 that isin contact with tissue 213. Otherwise, the incident light beam 214 istotally internally reflected. As a result, the medical device of FIGS.2A and 2B saves power because light energy is transmitted to the tissue213 only when it comes into contact with the tissue-contacting surface211.

FIG. 3A illustrates an embodiment of a first jaw member 120 that isoptically coupled to a light source 301. The light source 301 may be anoptical assembly that includes an LED (not shown) that generates lightand a beam-forming optical element (not shown) that forms the light intoa beam. Alternatively, the light source 301 is a light guide thatcarries light from an LED (not shown) to the first jaw member 110.

The light source 301 directs an incident light beam 214 at the tissuecontacting surface 211 of the first jaw member 110. The light source 301is positioned to direct the incident light beam 214 at a desiredincident angle 204 with respect to the axis 202 normal to thetissue-contacting surface 211 of the first jaw member 110. As describedabove, the incident angle 204 is selected so that it is greater than thecritical angle to facilitate total internal reflection when air 205 isin contact with the tissue-contacting surface 211 of the first jawmember 110.

The reflected light beam 216 is absorbed by a light-absorbent opticalelement 310 so that the reflected light beam 216 is not transmittedoutside of the first jaw member 110. In other embodiments, thelight-absorbent optical element 310 is replaced with a light-reflectiveoptical element, which may reflect the reflected light beam 216 back tothe tissue-contacting surface 211 of the first jaw member 110 or to anoptical element that carries the reflected light beam 216 away from thefirst jaw member 110. The light-absorbent optical element 310 may beformed of a material that dissipates heat generated

As illustrated in FIG. 3B, when the first jaw member 110 and the secondjaw member 120 grasp the tissue 213, at least a portion of the lightbeam 214, i.e., the transmitted portion 215, is transmitted to thetissue 213. The transmitted portion 215 of the light beam 214 thatpasses through the tissue 213 is absorbed and/or reflected by opticalelement 320 disposed in the second jaw member 120.

If the optical element 320 is light-reflective, it may be positioned atan angle with respect to the tissue-contacting surface 212 of the secondjaw member 120 so that the transmitted portion 215 of the incident lightbeam 214 that passes through the tissue 213 is reflected back to thetissue 213.

FIGS. 4A and 4B illustrate an end effector assembly that incorporatesfiber optic components 402 a, 404 a, 406 a, 402 b, 404 b, and 406 b. Asshown, the fiber optic components 404 a, 406 a disposed in the first jawmember 110 are the same as the fiber optic components 404 b, 406 bdisposed in the second jaw member 120. The first jaw member 110 includesa first lens 406 a that is optically coupled to a first light source 301a via an optical fiber 404 a. In this configuration, the first lightsource 301 a is not disposed within the jaw members 110, 120. The firstlight source 301 a, however, may be disposed elsewhere in the forceps10, the forceps 11, the generator 40, or the internal energy source 50.For example, the first light source 301 a may be disposed within thehandle 26, the housing 20, or the shaft 12 of the forceps 10.

The first light source 301 a generates an optical signal that istransmitted to the first lens 406 a via the optical fiber 404 a. Thefirst lens forms a first light beam 214 a and directs the first lightbeam 214 a towards the first tissue-contacting surface 211 of the firstjaw member 110 at a first incident angle 204 a with respect to an axis202 a normal to the first tissue-contacting surface 211. The firstincident angle 204 a is selected so that the first light beam 214 a istotally reflected 216 a from the first tissue-contacting surface 211when tissue does not contact the first tissue-contacting surface 211.The first jaw member 110 also includes a light-absorbent optical element310 a that absorbs the reflected light beam 216 a. In other embodiments,the light-absorbent optical element 310 a may be replaced with alight-reflective optical element.

Like the first jaw member 110, the second jaw member 120 includes asecond lens 406 b optically coupled to a second light source 301 b viaan optical fiber 404 a. The second light source 301 b (which may be adifferent type of light source than first light source 301 a or thesame) generates an optical signal that is transmitted to the second lens406 b via the optical fiber 404 a. The second lens 406 b forms a secondlight beam 214 b and directs the second light beam 214 b towards thesecond tissue-contacting surface 211 of the second jaw member 120 at asecond incident angle 204 b with respect to an axis 202 b normal to thesecond tissue-contacting surface 212. The second incident angle 204 b isselected so that the second light beam 214 b is totally reflected fromthe second tissue-contacting surface 212 when tissue does not contactthe second tissue-contacting surface 212. The second jaw member 120 alsoincludes a light-absorbent optical element 310 b that absorbs thereflected light beam 216 b. In other embodiments, the light-absorbentoptical element 310 b may be replaced with a light-reflective opticalelement.

As shown in FIG. 4B, when tissue 213 is grasped between the first jawmember 110 and the second jaw member 120, a portion of the first lightbeam 214 a is transmitted as light beam 215 a to the tissue and aportion of the second light beam 214 b is transmitted as light beam 215b to the tissue 213. In this manner, light can be applied to both sidesof the tissue 213 to seal the tissue 213 more quickly and evenly. Thetransmitted light beam 215 a is then absorbed by the light-absorbentoptical element 310 b and the transmitted light beam 215 b is absorbedby the light-absorbent optical element 310 a.

In an alternative embodiment, the light sources 402 a, 402 b may bereplaced by a single light source that emits a light beam that is splitand transmitted via two different fibers to the jaw members 110, 120,respectively. For example, a light source may emit a light beam that issplit and transmitted via fibers 404 a and 404 b to the jaw members 110,120, respectively.

FIGS. 5A-5C illustrate another embodiment that incorporates a movablelight source 501 and a crystal 503, e.g., a prism or other crystalstructure. As shown in FIG. 5A, the first jaw member 110 includes thecrystal 503 having four surfaces: a first crystal surface 502, a secondcrystal surface 504, a third crystal surface 506, and a fourth crystalsurface 508. The first crystal surface 502 forms a portion of thetissue-contacting surface 211 of the first jaw member 110. The movablelight source 501 is positioned to direct a light beam 512 at a firstincident angle 522 with respect to an axis 302 normal to the firstcrystal surface 502. The first incident angle 522 is selected so thatthe light beam 512 reflects from the first surface 502 as reflectedlight beam 514 when tissue is not in contact with the first surface 502.

The first jaw member 110, the light source 501, and the crystal 503 areconfigured so that the light beam 512 also reflects off of the secondcrystal surface 504 as reflected light beam 516, the third crystalsurface 506 as reflected light beam 518, and the fourth crystal surface508. Specifically, the first jaw member 110 may be a hollow structurethat is filled with air 210 and the crystal 503 has an index ofrefraction much greater than the air 210. As a result, total internalreflection can be achieved within the crystal 503 over a range of anglesthat are greater than the critical angle. The crystal 503 is alsoconfigured so that the incident angle of the light beam 512 with respectto the axis 302 normal to the second crystal surface 504, the thirdcrystal surface 506, and the fourth crystal surface 508 is greater thanthe critical angle. The movable light source 501 is positioned to createan incident angle with respect to the axes (e.g., axis 302) normal tothe crystal surfaces 502, 504, 506, 508 that is greater than thecritical angle.

As shown in FIG. 5A, the tissue-contacting surface 212 of the second jawmember 120 is coated with a light-absorbent optical material 530. Insome embodiments, the light-absorbent optical material 530 is a materialthat increases in temperature when it is illuminated with light.

Referring now to FIG. 5B, when tissue 213 is grasped between the firstjaw member 110 and the second jaw member 120, conditions of frustratedtotal internal reflection are created and the light beam 512 istransmitted through the tissue 213 to the light-absorbent opticalmaterial 530. As shown, the angle 524 of the transmitted light beam 515with respect to the axis 302, which is perpendicular to thetissue-contacting surface 211 of the first jaw member 110, is greaterthan the incident angle 522 according to Snell's law. As a result, thetransmitted light beam 515 passes through a portion of the tissue 213 atan angle 528 with respect to the axis 302.

As shown in FIG. 5C, the movable light source 501 is rotatable about apivot point 511 and translatable. As a result, the light beam 515 can berotated counter-clockwise or clockwise 510, or translated right or left513, to direct the transmitted light beam 515 through different portionsof the tissue 213. In this way, the transmitted light beam 515 can bescanned through multiple portions of the tissue 213. When the movablelight source 501 is rotated about the pivot point 511 of the first jawmember 110, the incident angle also changes to a second incident angle526. This process may allow larger tissue structures to be treated withsmaller light sources, may produce varying or different surgical tissueeffects (sealing versus cutting), and may provide more reliable andstronger seals.

In embodiments, the light source may be translatable to enable scanningof multiple portions of the tissue 213. The light source may also berotatable to enable changing of the incident angle with respect to thetissue-contacting surface of the optical element 503.

In alternative embodiments, the movable light source 501 may be replacedby a single fixed light source that transmits light to the jaw members110, 120 via a movable crystal or lens, which moves, e.g., rotates, toscan the light beam 512 over multiple portions of the tissue 213.

FIGS. 6A and 6B illustrate an embodiment in which a portion of the firstjaw member 110 is a crystal structure. As shown in FIG. 6A, the firstjaw member 110 includes a crystal portion 601 and a non-crystal portion603. The non-crystal portion 603 contains the light source 301 and areflective optical element 610, e.g., a mirror, which reflects lightgenerated by the light source 301 into the crystal portion 601. Thelight source 301 is positioned so that the incident angle 304 of thelight beam 612 with respect to the axis 302 is greater than the criticalangle. Thus, when tissue is not in contact with the first jaw member110, the light beam 612 is totally internally reflected from the firstcrystal surface 602.

The crystal portion 601 is configured so that the light beam 612 istotally internally reflected at the other crystal surfaces 604, 606,608. Thus, the light beam 612 propagates back and forth within thecrystal portion 601 until tissue 213 contacts the first crystal surface602.

As shown in FIG. 6B, the light beam 612 reflects from the first crystalsurface 602 at a first location 621, a second location 622, and a thirdlocation 623 as the light beam 612 propagates back and forth within thecrystal portion 601. When the first jaw member 110 and second jaw member120 grasp tissue 213, the tissue 213 makes contact with the firstcrystal surface 602 at the first location 621 and the second location622. This creates conditions of frustrated total internal reflection atthe first location 621 and the second location 622. As a result, a firstportion 615 of the light beam 612 is transmitted through the firstlocation 621 of the first crystal surface 602 to the tissue 213 and asecond portion 617 of the light beam 612 is transmitted through thesecond location 622 to the tissue 213. In this manner, the light beam612 can be evenly distributed through the tissue 213.

For purposes of safety, the second crystal surface 604 and the thirdcrystal surface 606 are coated with a reflective material 611 to preventthe light beam 612 from being transmitted to tissue or other objectsthat accidentally come into contact with the second crystal surface 604and/or the third crystal surface 606. In other embodiments, the secondcrystal surface 604 and/or the third crystal surface 606 may not becoated with the reflective material 611 to allow the user to performsurgical procedures using the second crystal surface 604 and/or thethird crystal surface 606.

As shown in FIGS. 6A and 6B, the second jaw member 120 includes alight-absorbent optical element 620 that absorbs the first portion 615of the light beam 612 and the second portion 617 of the light beam 612that pass through the tissue. The light-absorbent optical element 620 isdisposed a short distance away from the tissue-contacting surface 212 ofthe second jaw member 120. In some embodiments, the second jaw member120 may be a hollow jaw member having an optically-transparenttissue-contacting surface 212, which allows the first portion 615 of thelight beam 612 and the second portion 617 of the light beam 612 to passthrough the tissue-contacting surface 212 to the light-absorbent opticalelement 620.

FIG. 7 illustrates another embodiment of the first jaw member 110 andthe second jaw member 120. The first jaw member 110 includes a lightguide 701 having a first guide surface 702 that forms a portion of thetissue-contacting surface 212 of the first jaw member 110. The first jawmember 110 also includes multiple light sources 301 a-301 c. The lightsources 301 a-301 c generate multiple light beams 712 a-712 c that aredirected into the light guide 701. The light sources 301 a-301 c directthe multiple light beams 712 a-712 c at an appropriate angle withrespect to an axis normal to the first guide surface 702 so that themultiple light beams 712 a-712 c are totally internally reflected offthe first guide surface 702 and a second guide surface 706 when tissuedoes not contact the first guide surface 702.

The light guide 701 includes a light-absorbent optical element 704 atthe distal end of the light guide 701. The light-absorbent opticalelement 704 absorbs the multiple light beams 712 a-712 c that propagatealong the length of the light guide 701. When the tissue 213 comes intocontact with the light guide surface 702, portions 715 a-715 c of themultiple light beams 712 a-712 c are transmitted through the tissue 213to heat and seal the tissue 213. In this way, light is distributedacross the tissue 213.

As shown in FIG. 7, the multiple light beams 712 a-712 c reflect off ofdifferent portions of the first light guide surface 702 as the multiplelight beams 712 a-712 c propagate along the length of the light guide701. When the tissue 213 comes into contact with the first light guidesurface 702, portions of the multiple light beams 712 a-712 c aretransmitted only through those portions of the first light guide surface702 that are in contact with the tissue 213. In some embodiments, themultiple light sources 301 a-301 c may be configured to generatemultiple light beams 712 a-712 c, respectively, having differentwavelengths selected to produce a desired tissue affect.

Similar to the second jaw member 120 of FIGS. 2A and 2B, the second jawmember 120 is made of a light-absorbent optical element 220 that absorbsthe portions 715 a-715 c of the multiple light beams 712 a-712 c thatare transmitted through the tissue 213. In other embodiments, thelight-absorbent optical element 220 is replaced with a light-reflectiveoptical element, which may reflect the portions 715 a-715 c of themultiple light beams 712 a-712 c back into the light guide 701.

In alternative embodiments, the multiple light sources 301 a-301 c maybe replaced by a movable light source. For example, the light source maytranslate along the length of the light guide 701 to scan multipleportions of the tissue 213 (similar to the movable light source 501 inFIG. 5C).

FIG. 8 illustrates another embodiment of the first jaw member 110 thatincorporates multiple crystals 802, 804. The multiple crystals 802, 804are distributed along a longitudinal axis of the first jaw member 110and each crystal 802, 804 includes a first crystal surface that forms aportion of the tissue-contacting surface 211. In other embodiments, themultiple crystals 802, 804 are also distributed in rows along atransverse axis of the first jaw member 110.

The first jaw member 110 also includes multiple light sources 806, 808that generate light beams 812, 814 and direct them into respectivecrystals 802. In this embodiment, the light sources 806 direct the lightbeams 812 at a first angle into the crystals 802 so that the light beams812 are totally internally reflected and circulate within the crystals802 in a counter-clockwise direction when tissue is not in contact withthe tissue-contacting surfaces of the crystals 802. Similarly, the lightsources 808 direct the light beams 814 at a second different angle intothe crystals 804 so that the light beams 814 are totally internallyreflected and circulate within the crystals 804 in a clockwise directionwhen tissue is not in contact with the tissue-contacting surfaces of thecrystals 804.

As shown in FIG. 8, the light beams 812, 814 are transmitted into thetissue 213 from only those crystals 802, 804 whose firsttissue-contacting surfaces come into contact with the tissue 213. Andbecause the light beam 812 is circulating in a different direction fromthe light beam 814, the transmitted light beams 816, 818 pass throughthe tissue 213 in different directions.

The optical elements described above may be formed of any material thatfacilitates total internal reflection. In various embodiments, theoptical elements may be formed of sapphire crystal, ruby, YAG,alexandrite, flint, BK7 glass, crystal glass, or fused silica.

FIG. 9 is a flow diagram of a method of performing a tissue-sealingprocedure with light. After the procedure starts (step 901), tissue isgrasped between a first jaw member and a second jaw member of a medicalinstrument (step 902). Next, a tissue-contacting surface of an opticalelement of the first jaw member is illuminated with a light beam (step904). Then, the light beam is reflected from the tissue-contactingsurface when tissue does not contact the tissue-contacting surface ofthe optical element (step 906). Before the method ends (step 909), atleast a portion of the light beam is transmitted through thetissue-contacting surface of the optical element when tissue contactsthe tissue-contacting surface of the optical element (step 908).

FIG. 10 is a flow diagram of a method of performing a tissue-sealingprocedure with light. After starting (step 1001), at least one propertyof the tissue to be grasped between the first jaw member and the secondjaw member is determined (step 1002). Next, an incident angle at whichto illuminate the tissue-contacting surface of the optical element ofthe first jaw member with the light beam is determined based upon the atleast one property of the tissue (step 1004). Before the method ends(step 1007), a light source is adjusted to illuminate thetissue-contacting surface of the optical element of the first jaw memberwith the light beam at the incident angle (step 1006).

While several embodiments of the disclosure have been shown in thedrawings and/or discussed herein, it is not intended that the disclosurebe limited thereto, as it is intended that the disclosure be as broad inscope as the art will allow and that the specification be read likewise.Therefore, the above description should not be construed as limiting,but merely as exemplifications of particular embodiments. Those skilledin the art will envision other modifications within the scope and spiritof the claims appended hereto.

What is claimed is:
 1. A medical instrument, comprising: a first jawmember having a tissue-contacting surface; a second jaw member movablycoupled to the first jaw member, the first jaw member and the second jawmember cooperating to grasp tissue between the first jaw member and thesecond jaw member; and a light source that provides a light beam forsealing tissue, the light source optically coupled to the first jawmember so that the light beam is internally reflected from an interfacebetween the tissue-contacting surface of the first jaw member and airwhen tissue is not grasped between the first jaw member and the secondjaw member, and so that at least a portion of the light beam istransmitted through that portion of the tissue-contacting surface of thefirst jaw member that is in contact with the tissue when the tissue isgrasped between the first jaw member and the second jaw member.
 2. Themedical instrument according to claim 1, wherein the light source isselected from the group consisting of an optical fiber, a light-emittingdiode, a laser, a diode laser, and a fiber laser.
 3. The medicalinstrument according to claim 1, wherein the second jaw member includesa light-absorbent material that absorbs light that is transmittedthrough the tissue.
 4. The medical instrument according to claim 1,wherein the second jaw member includes a reflective material thatreflects light that is transmitted through the tissue.
 5. The medicalinstrument according to claim 1, wherein the light source is movable andis configured to move to a position based on at least one opticalproperty of the tissue while the tissue is in contact with at least aportion of the tissue-contacting surface of the first jaw member.
 6. Themedical instrument according to claim 1, wherein the light source isrotatable to selectively provide a light beam having a variable angle ofincidence with respect to an axis normal to the tissue-contactingsurface of the first jaw member.
 7. The medical instrument according toclaim 1, further comprising an optical element disposed in the first jawmember, the optical element having a side that forms at least a portionof the tissue-contacting surface of the first jaw member.
 8. The medicalinstrument according to claim 7, wherein the optical element is a lightguide that extends along at least a portion of a longitudinal axis ofthe first jaw member.
 9. The medical instrument according to claim 8,wherein a light-absorbent element or a light-reflective element iscoupled to at least a portion of a distal end of the light guide. 10.The medical instrument according to claim 7, wherein the optical elementis a crystal configured to circulate the light provided by the lightsource when tissue is not grasped between the first jaw member and thesecond jaw member.
 11. The medical instrument according to claim 7,wherein the optical element includes a plurality of crystals and thelight source includes a plurality of light sources coupled to theplurality of crystals, respectively.
 12. The medical instrumentaccording to claim 11, wherein each of the plurality of light sources isconfigured to provide a light beam having a different wavelength. 13.The medical instrument according to claim 7, wherein the optical elementis formed of a material selected from the group consisting of sapphire,ruby, YAG, alexandrite, flint, BK7 glass, and fused silica.
 14. Themedical instrument according to claim 7, wherein the second jaw memberincludes a second optical element having a side that forms at least aportion of a second tissue-contacting surface, further comprising asecond light source that provides a second light beam for sealingtissue, the second light source optically coupled to the second opticalelement so that the second light beam is totally internally reflectedfrom the interface between the second tissue-contacting surface of thesecond optical element and air when tissue is not grasped between thefirst jaw member and the second jaw member, and so that at least aportion of the second light beam is transmitted through that portion ofthe second tissue-contacting surface that is in contact with the tissuewhen the tissue is grasped between the first jaw member and the secondjaw member.
 15. The medical instrument according to claim 7, wherein thefirst jaw member is hollow and the optical element is disposed therein.16. The medical instrument according to claim 7, wherein the opticalelement forms at least a portion of the first jaw member.
 17. Aoptical-based tissue-sealing system, comprising: a housing; an endeffector assembly operably connected to the housing, the end effectorassembly including: a first jaw member having a tissue-contactingsurface; and a second jaw member movably coupled to the first jawmember, the first jaw member and the second jaw member cooperating tograsp tissue between the first jaw member and the second jaw member; alight source that provides a light beam for sealing tissue, the lightsource optically coupled to the tissue-contacting surface so that thelight beam is totally internally reflected from an interface between thetissue-contacting surface of the first jaw member and air when tissue isnot grasped between the first jaw member and the second jaw member, andso that at least a portion of the light beam is transmitted through thetissue-contacting surface of the first jaw member to the tissue whentissue is grasped between the first jaw member and the second jawmember; and a controller coupled to the light source, the controllerconfigured to control at least one parameter of the light beam.
 18. Theoptical-based tissue-sealing system according to claim 17, wherein theat least one parameter of the light beam is selected from the groupconsisting of intensity, wavelength, polarization, and angle ofincidence with respect to an axis normal to the tissue-contactingsurface of the first jaw member.
 19. The optical-based tissue-sealingsystem according to claim 17, further comprising a sensor configured tosense at least one optical property of the tissue, wherein thecontroller is configured to control at least one parameter of the lightbeam based upon the at least one optical property of the tissue.
 20. Amethod of treating tissue with an optical energy-based medicalinstrument, comprising: directing a light beam into at least one opticalelement of a first jaw member of an optical energy-based instrument witha light beam; reflecting the light beam within the optical element froman interface between a surface of the optical element and a media havinga low index of refraction; grasping tissue between the first jaw memberand a second jaw member of an optical energy-based medical instrument;and transmitting at least a portion of the light beam through atissue-contacting surface of the optical element to the tissue when thetissue is grasped between the first jaw member and the second jawmember.